There are known "disposable" bottles made of flexible plastic material which can be folded or rolled up after use to reduce their dimensions. This is useful in order to reduce the volume of waste to be disposed of.
These bottles are usually obtained by blowing, with relatively thin and pliable walls. One of these bottles is illustrated in EPA 525 908.
Unfortunately, due to the elasticity of plastic materials, the minimum dimensions obtained are never as limited as could theoretically be hoped for. In fact, as hard as the user tries to fold it as tightly as possible, the folded bottle always tends to unfold.
It is known to make containers of variable volumes which are held in variously contracted positions by differently shaped elements.
U.S. Pat. No. 4,456,134 provides for laces to be fastened to eyelets on the bottle lateral sides.
U.S. Pat. No. 4,592,492 and U.S. Pat. No. 4,157,103 show lateral protrusions which engage in tape eyelets.
These solutions call for the bottles to be moulded from sufficiently thick plastic material in order to form these types of fasteners, which are not obtainable by blowing. In fact, U.S. Pat. No. 4,157,103 appears to suggest applying the protrusions as separate parts, which is incompatible with the manufacture of disposable bottles. FR 2.504.095 describes a bottle which folds up concertina-fashion with fasteners for the various loops.
These fasteners must be extremely sturdy and require an economically inadmissible use of material.
It has also been suggested to keep highly flexible bottles in the collapsed position by applying an elastic element (for example a rubber ring), as shown in U.S. Pat. No. 3,424,218. This fastening requires a relatively long additional element in elastic material, differing from that of the bottle, thereby rendering the operations of recycling the materials more complicated. The use of an elastic ring makes it difficult to effectively counteract the tendency of the bottle to stretch back into shape.